Fluke 93 Service Manual page 137

CORRECTIVE MAINTENANCE
7
-
11
7
.
1
.
$.4
Defa
uft
signals
measured
in
the
digital Girovits.
The
Digital
Ai
PCB
is
provided
with large
I
meg
rated
ctrcults.
Fortesting the board,
tfie inpirt
signals
and
output signals
of
the large Integrated
circuits
are given
in
tables
7.2 up
to 7.5.
and
the
corresponding
figures.
These
signals
can be used
to
check
correct functioning of the large Integrated
Circuits
on the
digital
A1
PCS.
All
measurements
are
made
in
the
default
MASTER
RESET
condition
(start
the
measurements
in
the
SoopeMeter
using
MASTER
RESET).
A
MASTER
RESET
is
performed as
follows:
1.
Remove
all
signals
from the
Scope
Meter.
2
.
Turn
off the
Scope
M
eter
3.
Hold
down
the
LCD
key and
press the
ON/OFF
key sfmuttaneously.
Two
beeps
are audible,
and
ail
volatile
memories
(RAM
with battery backup) are
reset.
The
ScopeMeter
is
automatically set
to the
Meter
mode.
Use
another
oscilloscope with high Input
impedance and
1
0:1
probe
to
measure
the signals
on
the
integrated
circuits.
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AD1
ADO
St
ALE/AlJy
INST
BUSWIDTM
CLKOUT
XTAL2
XTAL1
z
i-i
irt
Z
<j
f
2^
s
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Figure 7.2 Microprocessor
D
120
T2CLK
VSS
(0}
RCADY
P2.4
"WSL/WR
PWM
T2CAP
P2
VPP (+5V)
VSS
(0)
VSS
(o)
H50.3
VCC
(-H5V)
VSS
(
0
)
H50.2
P2.6
PI-7
PT.6
PI.
MSO.l
HSO.O
HS0.3
VSS
(Oj
WSD.4
ST6613
911114